For providing services such as postal service and home-delivery service, dimensions (length, width, and height) of packages, cardboard boxes each containing a package, or others need to be measured to determine a charge classification.
Japanese Patent Application Laid-Open No. 2010-8352 discloses a method for measuring dimensions of a measurement target object such as a package. This method establishes a reference scale defining a reference of lengths (i.e., known lengths) on a surface of the measurement target object beforehand, captures an image containing the measurement target object for which the reference scale has been established, and calculates dimensions of the measurement target object on the basis of a relative positional relationship between the reference scale and the measurement target object in the image.